Adsorption Behavior and Corrosion Inhibition of EPP for Q235 Steel in H_2SO_4 Solution

摘要

The inhibition effect of N, n-diethylammonium O, o'-di(2-phenylethyl)dithiophosphate (EPP, [NH_2(Et)_2][S_2P(OCH_2CH_2Ph)_2]_2) against the corrosion of Q235 steel in H_2SO_4 solution was studied by weight loss measurement, potentiodynamic polarization and SEM(scanning electron microscope) techniques. The results show that EPP acts as an excellent corrosion inhibitor in 5% H_2SO_4 by suppressing simultaneously the cathodic and anodic processes via chemical adsorption on Q235 steel surface, which complies with the Langmuir adsorption isotherm. Polarization curves indicate EPP is a mixed-type inhibitor. The effects of temperature, acid concentration and immersion time were also studied.